Creality CR-2020 Gantry for E3d Titan Extruder - E3dv6 Optional

Cr-2020 gantry and titan mount.

Final versions:

16/08/2018
-Easy titled things
-Minor bugfixes and reinforcements


// -V2 A without M3x5 threaded inserts
// -V2 B with M3x5 threaded inserts
// -V2 e3dv6 A without M3x5 threaded inserts
// -V2 e3dv6 B with M3x5 threaded inserts


//UPDATE 27/07/2018:
//V1.1 Added

//UPDATE 31/07/2018:
//V1.2 in version:
// -A: upgraded v1.1 version making room for titan gear;
// -B: to use with M3x5 threaded inserts

//UPDATE 01/